1. Field of the Invention
The present invention relates to a liquid crystal compound, an optical film, and a method for producing an optical film.
2. Description of the Related Art
In the case where monochromatic light beam is transmitted through a λ/4 phase difference plate or a λ/2 phase difference plate, it is easy to convert the light into light having a wavelength with appropriate phase difference. However, in the case where white light having a plurality of monochromatic light beams therein is transmitted, it is difficult to convert all the light beams into ones having a wavelength with appropriate phase difference. The reason therefor is that materials constituting the phase difference plate have different phase difference with respect to the respective monochromatic light beams, and generally, a component having a shorter wavelength is more susceptible to phase difference. Thus, white light transmitted through the phase difference plate results in different phase difference with respect to the respective monochromatic light beams (a state of having different phase difference according to the wavelength is mentioned to have wavelength dispersion).
Accordingly, since white light obtained by light transmission through a phase difference plate has wavelength dispersion, there is a problem that polarized light converted by the phase difference plate due to a change in the polarization state at each wavelength would be colored.
In order to solve the aforementioned problems, broadband phase difference plates capable of providing uniform phase difference with respect to a wide-wavelength light have been investigated in various aspects. Specifically, compounds which exhibit reverse wavelength dispersion providing greater phase difference at a long wavelength have been investigated in various aspects (for example, JP2008-273925A, JP2009-274984A, and WO2012/147904A).